1. Field of the Invention
The present invention relates to an illumination apparatus, a light source apparatus using the illumination apparatus, and an image display apparatus. In particular, the present invention relates to a light source apparatus using a laser diode (LD) light source and a projector using the light source such as a projection display apparatus.
2. Description of the Related Art
In recent years, a projector capable of displaying a color image by using a fluorescent member (phosphor) that can convert blue light emitted from an LD light source into green light and red light has been developed.
The above-described projector is discussed in U.S. Patent Application Publication No. US2010/0328632 and U.S. Patent Application Publication No. US2011/0292349.
In the technique discussed in U.S. Patent Application Publication No. US2010/0328632, a color image is displayed by using blue light emitted from an LD light source in addition to green light and red light emitted as fluorescence light (phosphor light). In the technique, a fluorescence wheel having a diffusion layer capable of transmitting the blue light emitted from the LD light source and a fluorescent layer functioning as a fluorescent member is rotated. When the diffusion layer is irradiated with the blue light emitted from the LD light source, the blue light passes through the fluorescent layer, so as to be guided to an illumination optical system by a reflection mirror. On the other hand, when the fluorescent layer is irradiated with the blue light emitted from the LD light source, green light and red light are emitted in the light source direction, so as to be guided to the illumination optical system by a dichroic mirror.
In the technique discussed in U.S. Patent Application Publication No. US2011/0292349, blue light emitted from a blue light-emitting diode (LED) disposed separately from an LD light source is used in addition to green light and red light emitted as fluorescence light. As described above, the techniques for displaying a color image have been discussed.